This coil is being advertised at quite a few dealers now for $179.95. Which is great, available now for existing TDI owners. I had to chuckle though. They all are advertising it as “Whites 7.5″ x 12″ TDI HI-Q Dual Field Coil for MX Series Metal Detector”
Makes me wonder sometimes if I am the only one that notices stuff like this.
The 7.5” x 12” Hi-Q is a dual field coil with a fancy new name. A large outer coil with a small inner coil. If you use a small test nugget only the small inner coil is reacting. The larger outer coil adds more depth for larger targets.
The 12” round dual field will act the same way. Only the inner coil will respond to small targets, the larger outer coil the larger targets. As a round coil it has a larger total area than the Hi-Q elliptical so will get just a little more depth on large